7.2
In this topic, you will learn that:
• biology is the study of living organisms and what it means to be alive • living things move, reproduce, need nutrition, grow, respond, exchange gases, produce waste and need water • dead organisms were once living.
Characteristics of living things
Living things GROW as they get older
It has taken many years of observation and discussion for scientists to develop eight characteristics that all living things – plants, animals and even micro-organisms such as bacteria – have in common. To remember all eight characteristics, just remember: MR N GREWW.
All living things grow during their lives. Mushrooms start off as tiny spores. Humans are born as babies and develop into children, teenagers and then adults. Insects hatch from eggs as larvae and then metamorphose into adult insects (Figure 4). In every case, living things, when fully grown, resemble their parents.
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Interactive 7.2 Classifying living, non-living and dead
Living organisms have characteristics in common
Living things can MOVE by themselves
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Figure 1 Living things move.
Animal movements are easy to see. But do plants move? Look at the leaves on an indoor plant – they usually face the window (a source of light). Turn the plant around so that the leaves face into a darker part of the room. In a few days, the leaves will again be facing the window. The leaves have moved by themselves. Sunflowers turn their heads to follow the Sun as it moves across the sky each day.
Figure 3 Living things need nutrients to survive.
Living things can REPRODUCE
Figure 2 Living things reproduce. reproduction the production of offspring by a sexual or asexual process autotroph an organism that makes its own food heterotroph an organism that absorbs nutrients from other living things
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Living things can make new individuals that grow up to look like them. Animals mate and produce offspring, plants produce seeds that grow into new plants, and bacteria divide to produce more bacteria. Reproduction is the process by which living things make new life.
Living things need NUTRITION All living things need nutrients to survive. Animals obtain most of their nutrients by eating food and drinking. Plants absorb nutrients through their roots and fungi feed on decaying organisms. Plants are autotrophs, which means they make their own food. Animals and fungi are heterotrophs, which means they rely on other living things for food or nutrients.
Figure 4 Living things grow during their lives.
Living things RESPOND to change When an animal realises it is being chased, like the springbok in Figure 5, it runs. It is responding to stimuli (the sight and sound of a charging predator) or to changes in its environment (the sudden brush of leaves or
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